According to unnamed sources, Pro-Russian forces and civilian militias stormed the vessels late Thursday night. After several hours of intense exchanges that included warning shots fired by Ukrainian sailors and smoke grenades thrown by Moscow-backed forces, Russian flags were raised on the decks of the Khmelnitsky, Lutsk, Donbass, Kremenets, Borshiv and Ternopol.

An unsuccessful attempted was made to capture the Ukrainian Black Sea Fleet's flag ship, Slavutich. No casualties were reported in the raids.

The Russian Navy has indicated that the ships will be allowed to leave Sevastopol harbor once legal procedure for the vessels and crew are settled between the two sides.

Russia's navy has blockaded Ukrainian naval vessels stationed in Sevastopol harbor since the crisis in Crimea began on February 27-28.